There's no disputing that DAT has played its part in changing modern recording studios - and Casio's new DA7 looks set to spread the changes yet further afield.

ONCE IT WAS part of some vision of the future, where technology had finally delivered much that it currently only promises. Then it was an expensive reality - one that may or may not find favour with enough professionals to create the demand necessary to ensure its acceptance as a valid recording medium within the recording industry. Now it is a practical reality; a cost-effective means of producing high-quality recordings, finding itself in use in more recording studios with every day that passes. It is DAT: Digital Audio Tape.

While the Sony DTC1000ES quickly established itself as the industry-standard DAT machine at the professional end of the market (a position for which it is being challenged by Tascam's DA30), the budget/portable end of the market is still being fought over. One of the early favourites was Casio's DA1 - a relatively cheap portable which, inevitably, incorporated a number of shortcomings. Fifteen-bit, instead of full 16-bit, sample resolution, the lack of digital inputs and outputs, and the ability to record only at 48kHz marked the DA1 as a budget machine. However, it represented affordable access to DAT recording, and so sold well into the amateur and semi-professional markets.

When the DA1 gave way to the DA2, it too sold well, though - curiously - neither machine was handled by Casio themselves in Britain. The DA2 represented certain improvements over the DA1 but the main shortcomings remained - it still lacked digital ins and outs, recorded only at 48kHz and employed 15-bit sample resolution. The recent release of the DA7 brings the story up to date. The mastering-standard 44.1kHz sample rate is now available when recording from the digital inputs, and full 16-bit resolution is now standard. And, as if to confirm the DA-series' coming of age, Casio themselves are now handling its distribution.

This official endorsement appears to have been precipitated by the inclusion of a copy protection system in the DA7. Previously, the DA1 and DA2 had been able to copy from any source and allow unlimited copies of recordings - although all recording and reproduction could only be made via the machines' analogue interface. Such has been the threat of litigation in the US, Casio UK appear to have chosen to dissociate themselves from any possible trouble. Now, with the inclusion of the Serial Copy Management System (SCMS) in the DA7, Casio UK appear more at ease with the situation.

CALL THE DA

BRIEFLY, THEN, THE Casio DA7 is a fully-fledged, 16-bit resolution portable DAT recorder featuring digital inputs and outputs, sub-coding, and SCMS copy prevention. Recording is possible at 48kHz via the analogue inputs and 44.1kHz via the digital ins; playback of both formats is obviously also supported.

The machines "portable" status is fully supported by its carrying case, which should be quite adequate to protect it in the field - an additional bonus to the dedicated sample hunter. Power for portable applications is derived from a NiCad pack (supplied) which will support the unit for two hours continuous use on an eight-hour charge. Alternatively, the (supplied) AC adaptor can be used in the recording studio.

Connections to the DA7 are made using a panel on the right-hand side of the unit. Here you'll find analogue audio inputs and outputs on phono connectors, left and right mic inputs on quarter-inch jacks, and digital ins and outs on gold-plated phono connections (one for input, one for output).

The input selector, DAT cassette mechanism and eject button are on the upper panel (making rack installation difficult), leaving most of the action taking place on the front panel. Here, from left to right, you'll find a (3.5mm) headphone socket and volume control; LCD window governing most of the DA7's operation; time, counter reset and mode buttons; tape transport controls; record level control and power on/off switch. This switch is non-locking and the unit will automatically power down if it's not used for six minutes - potentially useful in the field, but this can be disabled (by holding down the tape stop button on power up) for studio applications.

The tape transport controls generally follow those of a conventional reel-to-reel or cassette machine. The Play, Stop, Pause, Rew and FF functions should all be self-explanatory, leaving only the Rec/Mute and Skip buttons outstanding. Skip follows the function of the same name found on a CD player - specifically allowing you to skip forwards and backwards between the start of the recorded tracks. Pressing Rec/Mute will take you into Record Standby mode. Immediately after pressing this button, the DA7 will record a five-second blank onto the tape which contains the relevant Start ID and Program Number sub-codes (more about this later). Once this is complete, the unit is ready to record - press Play to begin recording. While in Record Pause mode (after the recording of sub-code data), the record levels may be set using the ganged pots on the front panel - remember that even slightly overloading a digital recording produces unpleasant distortion rather than the tape compression characteristic of analogue systems.

To record using the digital input, you must first set the input selector to Digital. The message "Digital In" then appears on the LCD. The method of entering Record mode is similar to that for analogue signals except that no input level needs to be set. It's at this point that protected source material will make itself known by forcing the DA7 to leave Record mode and enter Record Pause mode, and show "Prohib" in the LCD (see below for full details of copying restrictions).

ON DISPLAY

THE LCD WINDOW is the communication centre of the DA7. Here you will find signal "ladders" for setting the record level, an indication of when the unit is switched to the digital input, the Program Number, and time displays. The time displays are cycled through by successive presses of the Time button and consist of the following: absolute time elapsed (ABS), program run time (PRG), remaining time (REM) tape counter and a table of contents (TOC). The TOC gives you a breakdown of what's on the DAT cassette currently loaded into the DA7, and includes the total number of audio programs and the total program time. All useful stuff.

Use of the LCD in conjunction with the Mode button also facilitates erasure of Start IDs, recording of Program Numbers and renumbering of programs.

"Maybe the inclusion of a copy-prevention system won't bother you - or maybe it will. Either way you're having a copyright restriction placed on your own material while SCMS' effectiveness against bootleggers remains questionable."

IN CODE

ONE OF THE significant operational differences between using an analogue tape machine and a DAT recorder revolves around DAT's ability to incorporate sub-codes in a recording. These vary slightly between different manufacturers' and different machines' implementation; here's a run down of the DA7's subcodes.

The codes take four forms: Abs Time, Start ID, Program Number and End Data. Taking these in sequence, the Abs(olute) code registers the elapsed tape running time from the start of the cassette. This is recorded by the machine automatically, but it's important to initialise tapes from the beginning and not to accidentally erase areas of this code when making subsequent recordings. The Start ID of a recording designates the start of that particular recorded program. These can be recorded with each recording as it is made (see above) or added after the recording is complete. The Program Number is recorded with the Start ID and designates a number to each program. In this way each recording can be given a number similar to those allocated to tracks on a Compact Disc. Unsurprisingly, End Data marks the end of a recorded program. This must always be registered manually (at least the machine isn't telling you how long your songs should be).

The DA7's manual points out that the availability of sub-codes gives rise to two types of blank areas on tape - those with sub-code but no audio (which it calls recorded blanks), and those without either (non-recorded blanks). It advises avoiding non-recorded blanks by allowing the DA7 to run on after an audio program has finished being recorded, and to begin a subsequent recording from within this area. Adopting this procedure ensures that the DA7 will always accurately display elapsed and remaining tape times.

DO YOU COPY?

ONE OF THE MOST significant aspects of the DA7 is the inclusion of the SCMS copy prevention circuitry. Let me make it quite clear that this circuitry is permanently operative; there is no way to switch it in or out.

There are two situations in which the SCMS plays no visible part in the use of the DA7. The first is when originating recordings from the DA7's mic inputs, the second is when recording and replaying via the analogue interface. Presumably, the designers have assumed that any recording originated via a microphone is certain to be the recordist's copyright, while anything likely to be subjected to successive analogue-to-digital and digital-to-analogue conversions is going to suffer intolerable signal degradation. In practice, however, neither is necessarily true.

Where the SCMS system comes into play is in conjunction with the digital interface. Should you make a digital recording from a CD with copy protection, for example, the SCMS will prevent any further digital copies being made. Meanwhile, recording a CD via the DA7's analogue inputs and then attempting to make digital copies of this will give you one copy-protected generation.

While all this has been arranged in the (debatable) interests of protecting record companies' copyrights, it also interferes with your use of the DA7 to make your own music - to which you obviously own the copyright. If you connect the DA7 to your mixing desk and make masters from your multitrack (or "live" from a sequencer), you'll almost certainly be going into it via the analogue inputs. In this case, you'll find that your DAT master will allow only one further generation of copies. Maybe this won't bother you - or maybe it will. Either way you're having a copyright restriction placed on your own material while SCMS' effectiveness against bootleggers remains questionable.

VERDICT

IN USE, THE DA7 performed well and produced the sort of quality that's made DAT famous. And while it's not the most compact DAT machine available (check out the Aiwa HDS1), the DA7 represents a compromise between portability and comfortable prolonged studio use - when small controls can become frustrating. And if your main use for a DAT machine is in the studio, it may be a compromise well worth making.

To my mind, the main advantage of using a portable DAT machine is that it gives you a mobile, high-quality recording system which is ideal for sampling "in the field" or even just transferring samples into your studio - after all, how many of us have a hi-fi and video setup in our studio for lifting the odd line of dialogue or a drum break?

The other likely application for a budget machine like the DA7 is for making master backups from another DAT machine or from a system like Digidesign's Sound Tools. When tested with recordings made on a DTC1000ES, the DA7 showed no signs of incompatibility and should perform quite satisfactorily - just remember SCMS.

Looking at the use of the SCMS system another way to that described above, the inclusion of copy protection is potentially limiting to your use of a DAT machine you've paid out your hard-earned cash for. It may not make us happy, but SCMS is likely to be here for the foreseeable future. We may have to learn to live with it.

On the subject of cash, it's encouraging to realise that alongside the improvements over the DA2, the DA7 actually represents a reduction in cost over the older machine. How often do you get to read a closing line like that?

Price £649.95 including VAT.

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